Low hcg but doubling?

Ok so I had a blood test on Monday and it was 24, then one on Wednesday and it was 55. My levels are low but they’re doubling correctly. No bleeding, have felt achy in my lower abdomen but that lasted about 2/3 days . Anyone else have low hcg levels but they’re doubling correctly? Anyone else had something like this happen too?

Here are some tests from Sunday, Tuesday and then Wednesday. As you can see there is some significant progress with the lines getting darker.